This invention relates to terminal blocks, and more particularly to a terminal block assembly which utilizes a printed circuit.
Terminal blocks are used in connection with a wide variety of electrical apparatus. One field in which they find extensive use is in above ground terminal enclosures for buried cable installations. It is typical in such installations to make service connections, cable splices, or cross connections above ground. To accomplish this, the cable is brought above ground at desired locations and the splice, connections to service lines, or cross connections are accomplished within a pedestal-type enclosure provided for that purpose. Typically, the enclosures mount boards to which terminal blocks are attached for making the connections.
A common form of terminal block used in such enclosures consists of a molded dished housing having a series of spaced openings in its face. A stud-type terminal extends through each opening and is connected by means of a nut to the housing. The housing is normally open to the back and wires joined by a sheath into a cable are individually mechanically connected, soldered or welded to the inner ends of the stud terminals. The dished housing is then commonly filled with a potting compound whose purpose is to protect the electrical connections made to the stud terminals within the housing and to provide a mechanical bond to maintain the terminals and conductors in place. Such terminal blocks can be screwed to a flat support with the stud terminals projecting outwardly to allow for manual connections to the terminals extending from the front of the block.
Such typical terminal block construction has several disadvantages. It is very costly to manufacture, in part because it requires considerable manual assembly particularly in connection with the mounting of the terminals and connecting the wire conductors to the terminals within the shell. They are also prone to mechanical and electrical failures because of separation of potting compound from the housing and the resultant bridging of terminals in the housing by moisture migration to the end that there is a failure in the electrical circuit integrity. Such blocks are also prone to erroneous wiring and poor connections because of the manual wire wrapping which is involved.
A terminal block in accordance with the present invention employs printed circuit techniques to provide an economical, yet structurally and electrically sound, terminal block of consistent quality.